Oxygen electrodes have been used in a variety of battery systems. For example, a well known zinc/potassium hydroxide battery includes a carbon-PTFE oxygen electrode and a Zn/KOH electrode having a separator interposed therebetween. Oxygen from the air enters the oxygen electrode of the battery through an aperture in the positive terminal and permits the discharge reaction to proceed. A PTFE membrane is disposed between the aperture and the oxygen electrode. Such a battery is generally not rechargeable, and is used to power small devices such as watches and the like.
A number of patents describe oxygen cathodes incorporating carbon particles or catalyst particles in a hydrophobic polymer such as PTFE, as a single layer or as a multilayer laminate. See Blanchart et al., U.S. Pat. No. 4,536,272, issued Aug. 20, 1985; Solomon et al., U.S. Pat. No. 4,518,705, issued May 21, 1985; Solomon, U.S. Pat. No. 4,500,647, issued Feb. 19, 1985; Solomon et al., U.S. Pat. No. 4,456,521, issued Jun. 26, 1984; Rogers, U.S. Pat. No. 4,364,805, issued Dec. 21, 1982; and Gestaut, U.S. Pat. No. 4,350,608, issued Sep. 21, 1982. A variety of methods for making oxygen electrodes are known; see, for example, Kato et al., U.S. Pat. No. 4,985,775, issued Jan. 23, 1990; Feigenbaum et al., U.S. Pat. No. 4,728,533, issued Mar. 1, 1988; Blanchart et al., U.S. Pat. No. 4,696,872, issued Sep. 29, 1987; Heffler, U.S. Pat. No. 4,104,197, issued Aug. 1, 1978; Sauer, U.S. Pat. No. 4,336,217, issued Jun. 22, 1982; Baker et al., U.S. Pat. No. 3,935,029, issued Jan. 27, 1976. Known oxygen electrodes have, however, generally been designed to generate electrical energy rather than heat and to participate in the reaction during discharge.
Large lead-acid batteries are commonly used in automobiles and other vehicles for purposes of starting, lighting and ignition (SLI). It is well known that the cranking capacity of a lead-acid battery decreases at lower temperatures, sometimes preventing the battery from having enough power to start the vehicle. This problem is particularly acute in cold climates. The present invention, in one aspect, addresses this problem.